Substituting an exclamation point for his inconvenient last name, Jeb! has officially entered the presidential race. Why isn’t everyone else quaking in fear?

I can see why Hillary Clinton, the Democratic front-runner who also downplays a familiar surname, might welcome Jeb Bush’s candidacy. If the general election is Bush versus Clinton, the dynasty issue becomes a wash. Americans would just have to deal with the fact that these two families are never, ever going away.

But while Clinton looks like a lock to win her party’s nomination, at this point Bush — who unveiled his Jeb! campaign logo Sunday — can’t even be considered the favorite to win his. He is certainly in the top tier of GOP candidates, and his fundraising prowess may eventually wear down his rivals. But all Bush managed to do in the long pre-announcement phase of his campaign was to send his polling numbers into a swoon.

In March, a Post-ABC News poll found Bush favored for the nomination by 21 percent of Republican-leaning registered voters — a full eight points ahead of the rest of the field. But the same poll in May found him at just 10 percent, tied with his onetime protege, Sen. Marco Rubio of Florida, and slightly behind the co-leaders, Wisconsin Gov. Scott Walker and Sen. Rand Paul of Kentucky, each at 11 percent.

How did Bush manage to fall back into the pack? Mostly, it had to do with that troublesome family name. He spent the better part of a week struggling to answer a simple question about the most fateful decision his older brother, George W. Bush, made as president: Knowing what we know now, would he have invaded Iraq?

During his official presidential campaign launch, former Florida Governor Jeb Bush warned that country is on "a very bad course," but he has decided to fix it by running for president. (AP)

Jeb Bush’s first answer was yes. The next day, pressed to explain, he said he had misunderstood the question. The following day, he said it somehow dishonored U.S. troops to even ask the question. Finally, apparently having inflicted all the gratuitous self-injury he could stand, he changed his answer to no.

The episode cost Bush something valuable: his aura of inevitability.

Bush’s appeal to the Republican Party is largely based on the premise that he can beat Clinton. He is a proven vote-getter in his home state of Florida, which the GOP probably must take to have a shot at winning the presidency. And while he holds deeply conservative views on some issues, he is seen as moderate in the context of today’s Republican Party — and potentially more appealing to independent voters than many of his competitors.

Additionally, Bush’s wife, Columba, is from Mexico, he is fluent in Spanish and he takes a compassionate position on immigration. All of this might help make the GOP more competitive among Latinos, who voted Democratic by 71 percent in 2012.

From the beginning, it looked as if Bush’s biggest problem would be convincing primary voters that he’s not a RINO (Republican In Name Only) and that his views are sufficiently conservative for a party that has moved far to the right. Then, after winning the nomination, he would have to shift back toward the center — but not so abruptly that he disillusioned true believers.

None of this is impossible, but it requires a candidate who is light on his feet. So far, though, Bush has been stumbling around in clodhoppers.

Now his most urgent task is to convince the Republican establishment that he — not Rubio, Walker, or anyone else in the GOP multitude — should still be considered the smart money’s bet to defeat Clinton. Bush’s fundraising advantage should help: His super PAC is expected to come close to raising $100 million. Then again, these days, any candidate who manages to recruit a supportive billionaire can stay in the race pretty much indefinitely.

Bush has promised to “campaign hard” in Iowa, where Republican caucus-goers are deeply conservative. A recent Des Moines Register poll in the state showed Bush tied with former Arkansas Gov. Mike Huckabee for fourth place, with Walker, Paul and political novice Ben Carson leading the way.

Still, national polls indicate that Bush enters the race with as good a shot at the nomination as anyone. He is smart, experienced and deeply informed about domestic policy issues such as education. In his Florida campaigns, he was a skillful and indefatigable campaigner.

Ultimately, however, he will have to make uncomfortable judgments about his father’s and brother’s presidencies if he hopes to convince anyone that he is, indeed, his own man. The logo is Jeb! but voters do know his last name.

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Eugene RobinsonEugene Robinson writes a twice-a-week column on politics and culture and hosts a weekly online chat with readers. In a three-decade career at The Washington Post, Robinson has been city hall reporter, city editor, foreign correspondent in Buenos Aires and London, foreign editor, and assistant managing editor in charge of the paper’s Style section. Follow